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Tankless water heaters. What a load...

12-29-2008, 09:20 AM

Here. This is out of Consumer Reports.

Heating water accounts for up to 30 percent of the average home's energy budget. Some makers of gas-fired tankless water heaters claim their products can cut your energy costs up to half over regular storage heaters. So is it time to switch?

Probably not. Gas tankless water heaters, which use high-powered burners to quickly heat water as it runs through a heat exchanger, were 22 percent more energy efficient on average than the gas-fired storage-tank models in our tests. That translates into a savings of around $70 to $80 per year, based on 2008 national energy costs. But because they cost much more than storage water heaters, it can take up to 22 years to break even—longer than the 20-year life of many models. Moreover, our online poll of 1,200 readers revealed wide variations in installation costs, energy savings, and satisfaction.

With the help of an outside lab, we pitted Takagi and Noritz gas-fired tankless water heaters against three storage water heaters. EvenWe didn't test electric tankless heaters because many can't deliver hot water fast enough to replace a conventional water heater if ground­water is cold. in areas with warm groundwater, most homeowners would need to upgrade their electrical service to power a whole-house tankless model.

Our tests simulated daily use of 76 to 78 gallons of hot water. That's the equivalent of taking three showers, washing one laun­dry load, running the dishwasher once (six cycles), and turning on the faucet nine times, for a total of 19 draws. While that's considered heavy use compared with the standard Department of Energy test, we think it more accurately represents an average family's habits. We also ran more than 45,000 gallons of very hard water through a tanked model and a Rinnai tankless model to simulate about 11 years of regular use.

Here's what else we found:

Water runs hot and cold
Manufacturers of tankless water heaters are fond of touting their products' ability to provide an endless amount of hot water. But inconsistent water temperatures were a common complaint among our poll respondents. When you turn on the faucet, tankless models feed in some cold water to gauge how big a temperature rise is needed. If there's cool water lingering in your pipes, you'll receive a momentary "cold-water sandwich" between the old and new hot water. And a tankless water heater's burner might not ignite when you try to get just a trickle of hot water for, say, shaving.

Nor do tankless water heaters deliver hot water instantaneously. It takes time to heat the water to the target temperature, and just like storage water heaters, any cold water in the pipes needs to be pushed out. And tankless models' electric controls mean you'll also lose hot water during a power outage.

Up-front costs are high
The tankless water heaters we tested cost $800 to $1,150, compared with $300 to $480 for the regular storage-tank types. Tankless models need electrical outlets for their fan and electronics, upgraded gas pipes, and a new ventilation system. That can bring average installation costs to $1,200, compared with $300 for storage-tank models.

Tankless units might need more care
During our long-term testing, an indicator on the tankless model warned of scale buildup. We paid $334 for special valves and a plumber to flush out the water heater with vinegar. Many industry pros recommend that tankless models be serviced once a year by a qualified technician. Calcium buildup can decrease efficiency, restrict water flow, and damage tankless models. Experts suggest installing a water softener if your water hardness is above 11 grains per gallon. Ignoring this advice can shorten your warranty.

Efficient storage models are pricey
We also tested the $1,400 Vertex, a high-efficiency storage water heater by A.O. Smith. The manufacturer claims its installation costs are similar to a regular storage model. But its high cost offsets much of the roughly $70 per year the Vertex will save you. Instead, we recommend buying a conventional storage water heater with a 9- or 12-year warranty. In previous tests, we found that those models generally had thicker insulation, bigger burners or larger heating elements, and better corrosion-fighting metal rods called anodes.

So basically Consumer Reports is verifying pretty much everything those of us that have been screwing around with these things have been saying. Believe me, we have seen these products 25 years ago and had allthe same issues with them. In fact, most of those have long since been scrapped for more conventional heaters.

Indirect heaters use a boiler to heat a quantity of hot water. The storage tank is super insulated and has very very low standby loss. The recovery of these units if properly sized will allow you to virtually run hot water all day long.

i installed the 6.9 noritz i had sitting around my shop for the last 3 years

i convinced joey that it's for real life testing. we're taking one for the team

basically our 20 year old 40 gallon hoyt gas heater is starting to show signs of dying joey complained of brown water when filling the tub. she also tested the cold, ok

so i installed the tankless outdoors, close to my gas, and water lines. a pretty simple install based on my location of choice. i've only taken 1 shower since i finished yesterday afternoon. i will let this run till april and get a real life comparison of gas and convenience.

i did shut off the tank heater both gas and cold inlet. so at this point, i have no standing pilot lite in the house.

i'll be very curious to see what the takless will do with our hi-efficiency washer that cycles the fill valve

so i will be starting a thread in the next couple days to track my findings.

remember i've been real, real hard on the false promises that tankless companies have promoted. lets see if i was right or wrong

Comment

Situations where a tankless water heater might be a good option.Both examples are new construction or substantial remodel.New construction takes into account that a gas line and flue would have to be run to the heater (whether conventional or tankless) anyway, so only the difference in installation would be considered in the cost calculations. Occasional maintenance would still be required.

1)Pool or guest house where hot water demand is sporadic.
2)Vacation home that sits empty most of the time.

Both of these applications have opportunities for substantial stand by heat loss for a conventional wh due to the extended periods they sit idle. Of course, the vacation home loss can be partially reduced by the simple act of shutting the heater off when the house is vacant.

i installed the 6.9 noritz i had sitting around my shop for the last 3 years

i convinced joey that it's for real life testing. we're taking one for the team

basically our 20 year old 40 gallon hoyt gas heater is starting to show signs of dying joey complained of brown water when filling the tub. she also tested the cold, ok

so i installed the tankless outdoors, close to my gas, and water lines. a pretty simple install based on my location of choice. i've only taken 1 shower since i finished yesterday afternoon. i will let this run till april and get a real life comparison of gas and convenience.

i did shut off the tank heater both gas and cold inlet. so at this point, i have no standing pilot lite in the house.

i'll be very curious to see what the takless will do with our hi-efficiency washer that cycles the fill valve

so i will be starting a thread in the next couple days to track my findings.

remember i've been real, real hard on the false promises that tankless companies have promoted. lets see if i was right or wrong

rick.

I hope you pulled a permit!

spodelee

Until lions have their own storytellers, stories of the hunt shall always glorify the hunter

That above didn't mention the COST it takes to repair these units when they fail, control modules and flow switches, compartment!

A lot of people who own these glorify them until they break, and then they create another user name asking for information how to fix them under 8 days time. Oooooh damn bad time to be married to the wifey!

Comment

Lets see here, my dad has a super store as an extra zone of his furnace and never wants for hot water. All I know is if my 20-25 year old no name gas fired big old tank, no hard to replace parts, water heater ever gives up, thats what I am installing.

i installed the 6.9 noritz i had sitting around my shop for the last 3 years

i convinced joey that it's for real life testing. we're taking one for the team

basically our 20 year old 40 gallon hoyt gas heater is starting to show signs of dying joey complained of brown water when filling the tub. she also tested the cold, ok

so i installed the tankless outdoors, close to my gas, and water lines. a pretty simple install based on my location of choice. i've only taken 1 shower since i finished yesterday afternoon. i will let this run till april and get a real life comparison of gas and convenience.

i did shut off the tank heater both gas and cold inlet. so at this point, i have no standing pilot lite in the house.

i'll be very curious to see what the takless will do with our hi-efficiency washer that cycles the fill valve

so i will be starting a thread in the next couple days to track my findings.

remember i've been real, real hard on the false promises that tankless companies have promoted. lets see if i was right or wrong

rick.

get Joey to let you install the other device with an on demand water heater in it and you'll have a report worth talking about!!

so i installed the tankless outdoors, close to my gas, and water lines. a pretty simple install based on my location of choice. i've only taken 1 shower since i finished yesterday afternoon. i will let this run till april and get a real life comparison of gas and convenience.

And that, ladies and gentlemen, is why these technological wonders are really not suitable for installation in the North country. Unless the customer is prepared to accept the inconveniece and added costs, as I presume is done in other parts of the world, they are better off with a storage tank.

Comment

I have two on my home and while they are worth it to me because they really didn't cost me anything and I like the continuous hot water, I can't in good conscience recommend tank-less to our clients. We sell them only when a "know it all - researcher type" calls and wont listen to reason otherwise.

I still think there is room in the marketplace for a HIGH QUALITY TANK (not a weeny tank with a 6 year warranty that fails at 7 years) 90%+ AFUE water heater at a REASONABLE price. Haven't seen anything that meets that criteria yet.

Everything I have seen so far has a 10 year tank warranty and costs 3K+ wholesale. Just stupid.

We'll just stick with the good ol' 40 gal for a while.

spodelee

Until lions have their own storytellers, stories of the hunt shall always glorify the hunter

Comment

I have been saying the same thing for years, but I will say it again. Tankless water heaters are not for everyone. I get calls every week for people asking about them. I have only found a handful of people so far that have a situation where a tankless would be better then a tank style water heater.

Comment

I have yet to install one. Everyone that has asked me about them has backed down at my price. I called one lady for a follow-up, and she said she got a cheaper bid, and I actually bid it low just because I wanted to get some experience installing them!!! It seems the local cheapo-plumbers are already on the bandwagon of tankless heaters, so I have given up. Now anytime I get a call about tankless heaters, I give them a referral to another plumber. He is "green-certified" or some such crap. He doesn't have drain equipment, so he gives me his drain calls in exchange for anyone who calls me needing "green" plumbing or remodel work...both of which I could care less about.
I'll probably never install one as I am getting away from the water heater business. Give me a 300' orangeberg sewer that needs digging...(I got one of those this evening.) You can have these stupid tankless installs. We'll see who makes the real money and reputation over time.